Seamless steel pipe: Seamless steel pipe has a hollow section and is widely used as a pipeline for conveying fluids, such as pipelines for conveying oil, natural gas, gas, water and some solid materials. Compared with solid steel such as round steel, steel pipe has the same bending and torsion strength and lighter weight. It is a kind of economic cross-section steel, widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipe, automobile transmission shaft, bicycle frame and steel scaffolding used in construction and other steel pipe manufacturing ring parts, which can improve the utilization rate of materials, simplify the manufacturing process, save materials and processing hours. It has been widely manufactured with steel pipes.